Independent Power - Off The Grid Computing

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My career has been in the fields of electronics and computing. Usually working as a programmer. I was an early adopter of Java (a development language), and have been working Java now for about 11 years (About the same time we moved here.). So as you can imagine, my biggest concern about living off the grid was having adequate power, and whether my computers and other electronic equipment would function properly. I've had servers here running 24/7, so reliability was and still is a must.

I was also a musician for many years and so I was really interested to see whether recording equipment would operate properly, and quietly. The results have been surprising, and I'll share with you what I've learned

First let me point out that the most critical piece of equipment you need after a good generator is a good inverter. An inverter with a built in charger circuit will charge batteries from your generator, and after charging will turn the DC power in your batteries back in to 120V AC current like you use in your house. Unless you have a unique situation where power needs are minimal, try to get at least a 3,000 watt unit. There are cost savings and a more rugged design for larger inverters. Then the path to solar power and complete self sufficiency is very straight forward. Just add panels and batteries until the generator is not needed except for emergencies.

There is almost always a trade off between reliability and technical sophistication. The more complex the equipment and the higher the parts count, the lower the reliability. With the advent of computers and better processing of silicon for transistors, and improved power devices like high power MOSFETs and microprocessors, inverters are far more reliable than they used to be. In the case of today's high quality inverters you can count on high reliability and excellent power quality.

This is important! Don't scrimp on the inverter! The equipment I'm describing here is commercial grade and there are many good brands. There are cheap inverters everywhere that are very low grade and not suited to run your home. Shop around, get a good deal, but don't be penny wise and pound foolish. Buy high quality. It's the cheapest way to go in the long run. I have links on this site for a few inverters that I think are very good.

Pure or Modified Sine Wave?

What manufacturers are referring to is the distortion of the waveform produced by the inverter. Pure sine wave is the best, but I have three Xantrex 3624's that I use here and they are modified sine wave inverters. They are great! I've really appreciated their quality. However, OutBack, and others are now producing super reliable pure sine wave inverters that would be a better choice. However, they cost a little more.

The distortion of the AC can cause motors to be noisier, and I run a 3/4 HP deep well 240v pump with mine and I've had very reliable service from the well. So if you hear disparaging words about pump life and modified sine wave inverters I would take it with a grain of salt. My experience has been nothing but positive. There should be a small improvement in efficiency when driving motors, solenoids, and the like, but I'm sticking with what I've had good luck with...

There are situations that I've run into where a pure sine wave inverter would make a nice difference. First, a UPS doesn't like the wave form distortion of a modified sine inverter. There is slightly more RF noise generated by the inverter, but not much. The biggest issue I've seen is with marginal power supplies like some 'wall warts'.

In some cases (like analog power supplies) they designer relies on the high peak voltage of a pure sine wave in order to get sufficient voltage for his internal analog regulator. In a case like this if there is a big transient load (like a pump motor starting) the device will quit for an instant. This is ugly if it's your DSL modem as in my case. This is not the fault of my inverters, but the result of marginal design of the modem. My solution is to use a AC voltage regulator which works out fine, and provides cleaner power for critical devices.

Computers or devices that use digital switching power supplies are no problem.

The only other issue I've seen, is that although the relays that switch from generator output to inverter output and back, are not fast enough in some cases. I have one inverter that I use for critical circuits that is never switched. I use my other two inverters for charging and running the water pump and non-critical power circuits. For most appliances like TVs, recorders and etc. the switching delay is more than fast enough and you will most likely never have a problem. I've only had problems with some (not all) computers.

If you were to use a pure sine wave inverter you could use a UPS and that would solve the issue of slow relays nicely, if your computer is picky like mine. A laptop or notebook computer could care less... either will work great.

Printers

Jet printers are very economical with power, but Laser printers and a few others can be power hungry. Take a look at power consumption, stand-by or idle power consumption is the most critical.

Finally

There are at least two different direct to satellite ISP services that allow you high speed internet service without a phone line. Life has never been better for computer people to work off the grid. You can live anywhere, and still be in touch and productive.

After 11 years I can truthfully say that living out here has been wonderful. Smog-free, quiet, with space all around us. I'm grateful for our blessings. I hope more people will be able to do what we've done and enjoy the benefits the way we have.